NOTE: Please excuse the poor quality of Arabic typography. It is not trivial in the open source world.
By verbal forms I mean syntactic variations on the 3-letter roots that generate both new verbs and new nouns. These variations are used by convention among Arabic speakers.
Such forms qualify the root verb, its primary actors (the subject and the object), and how they relate to the web of facts. In Arabic, "verb" translates as فـﹺـعل literally the "deed" or "action". The relationships between the actors and the facts (places, things, states) are altered in each verbal form.